Definition: A pilot study is a practice / small-scale study conducted before the main study.
A pilot study is an initial run-through of the procedures to be used in an investigation; it involves selecting a few people and trying out the study on them. It is possible to save time, and in some cases, money, by identifying any flaws in the procedures designed by the researcher. A pilot study can help the researcher spot any ambiguities (i.e. unusual things) or confusion in the information given to participants or problems with the task devised.
Sometimes the task is too hard, and the researcher may get a floor effect, because none of the participants can score at all or can complete the task all performances are low. The opposite effect is a ceiling effect, when the task is so easy that all achieve virtually full marks or top performances and are “hitting the ceiling”. Therefore, piloting means checking the design of a study before conducting it in full so that if there are any differences between conditions, they will show up in the results.
Questionnaires or surveys or often subject to a pilot study. This enables the researcher to establish how easily questions are understood, how long the questionnaire takes to complete, etc. Modifications can then be made to produce a final questionnaire for the main study. A little time invested early on in the design of a study or questionnaire pays off in terms of the main study being well thought through